DynamoDB ReturnValues UPDATED_OLD in AppSync

Question

Im trying to update an item attribute in a DynamoDb table with AppSync. Once successful i want to use the previous value of that attribute as the key in my next call (I'm using pipeline resolvers).

To achieve this with DynamoDB you just set UPDATED_OLD as the return value.

I cannot find any documentation for specifying the return value of a DynamoDB resolver for AppSync. Ive tried the following.

{
  "version" : "2018-05-29",
  "operation" : "UpdateItem",
  "key": {
        "id": $util.dynamodb.toDynamoDBJson("foo")
      },
   "condition" : {
   "expression" : "attribute_exists(id)"
    },
    "update" : {
    "expression" : "SET bar = :bar",
    "expressionValues" : {
        ":bar" :  {"S" : "$bar"}
      }
    },
    "returnValues": "UPDATED_OLD"
  }

But its not valid syntax.

"message": "Unsupported element '$[returnValues]'."

score 4 · Accepted Answer · answered Apr 15 '19 at 17:22

4

The returnValues is not a valid field for the request mapping template of AppSync with DynamoDB. By default AppSync uses the ALL_NEW parameter for updates.

answered Apr 15 '19 at 17:22

Vasileios Lekakis

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I was afraid that this were the case. Thank you for confirming it. Hopefully it will be rectified in some future update to make AppSync even more viable. – Daniel Wennberg Apr 16 '19 at 07:19
1

I will take it to the team as a feature request – Vasileios Lekakis Apr 16 '19 at 19:14
1

Is this still the case? – David Perez Dec 26 '19 at 23:24
@VasileiosLekakis Is there a Github issue associated with this feature request? This would be a valuable addition – bingles Feb 02 '20 at 03:12
@bingles we don't have track feature requests as Github issues at AWS Appsync like they do for AWS Amplify. – dbala Feb 12 '20 at 00:57
As for DeleteItem it return ALL_OLD, which makes sense. – webjay May 09 '20 at 11:45

DynamoDB ReturnValues UPDATED_OLD in AppSync

1 Answers1